1. Field of the Invention
This invention relates to a method for manufacturing a heat insulating pad material having an aesthetic appearance by the use of an expansion-molded article produced through the in-mold expansion molding of expandable resin beads, and the heat insulating pad material thus manufactured. More specifically, the invention is directed to the use of a heat insulating pad material for a battery shield, and provides a heat insulating assembly for a battery, which prevents electric discharge in the winter and suppresses temperature rise in the summer.
2. Statement of Related Art
As heat insulating pad materials, plastic foams such as an urethane foam as well as a variety of materials are used generally to accommodate every use or application where heat insulation is needed.
For a battery or other objects where the prevention of electric discharge is necessitated at low temperatures in the winter and the prevention of temperature rise is necessitated at high temperatures in the high summer to avoid evapotranspiration of the electrolyte liquid, a heat insulating pad material thereof is required to have a wide variety of qualitative characteristics such as heat insulating and heat retaining properties in a wide temperature range of from low temperatures in the dead of winter to high temperatures at the height of summer, non-embrittlement and heat reserving and air tightness at low temperatures, conformity to a battery with no interstices, simplicity and swiftness of use as a battery shield at battery works, ease of removal and fitting of a discharged battery upon exchanging, resistance to oils, resistance to chemicals, resistance to high temperatures, recycling possibility, large section thickness (8 to 10 mm), economy, high-quality feeling, etc.
However, the aforesaid heat insulating pad materials used in the past cannot meet all of the qualitative characteristics mentioned above and can meet only a few of them. As examples of heat insulating assemblies for batteries required to have these characteristics, there are known a heat insulating assembly enveloped by a urethane or extruded mat around a battery and fastened thereon by a band; a heat insulating assembly covered around the outer surrounding of a battery with a heat-retaining cover made by filling polyester sponge and glass fibers within its facing and flattening the surrounding of the facing; etc.
The heat-retaining battery cover currently used is suited to heat retaining and heat insulating purposes, but has difficulties in that many steps are required for the production thereof, which necessitate a great deal of work and a high cost. Moreover, because it is made of a composite material, the cover has problems in recycling possibility and devoid of ease of mounting on and dismounting from a battery and fitness to the battery. Thus heat insulating pad materials sufficiently satisfying all of the characteristics have not yet been found.
In order to cope with the drawbacks above, the present invention has been accomplished.
Accordingly, an object of this invention is to provide a heat insulating pad material which it is easy and simple to fabricate out of a single kind of material.
Another specific object of this invention is to provide a heat insulating pad material satisfying the qualitative characteristics required for a battery shield (heat-reserving pad), viz., thereby providing a heat insulating assembly for a battery that has a beautiful appearance, enables the prevention of electric discharge in the winter and impeding of the temperature rise in the summer, thereby avoiding evapotranspiration of the electrolyte and facilitating the dismounting and mounting of the pad upon changing of a discharged battery.
The above and further objects and advantages of this invention will become more readily apparent from the following description.